A modified culture medium was developed for the purpose of isolating and characterizing the enterobacterias, giving special attention to the Salmonella strains that ferment lactose. In this "Modified Medium" the colonies of the two strains of Salmonella show a morphological similarity. This does not occur with other culture media of enterobacteria, in which the basic carbohydrate is lactose. The Modified Medium is a modification of the Enteric Agar in which the lactose was substituted by xilose and L-lisine. It was verified that there is a possibility of differentiating between the different groups of enterobacteria by using a culture medium with no lactose and using xilose L-lisina as a differentiating system. The Modified Medium was also evaluated quantitatively comparing its enriching or inhibiting power with the Hektoen Enteric Agar, Brilliant Green Agar and the SS Agar media in relation to the different groups of enterobacteria.
Enterobacterias; Salmonella, positive lactose; Culture medium